When you click with a history highlighted to export, the Add dialog (Figure 97) contains a number of fields with either default or empty values, described below.
All fields in this dialog apply separately to each highlighted (for export) history, as follows:
-
Name
Read-only Niagara component name for the Bacnet log descriptor, which defaults to the combination of:
trendLog_<instance number>. -
Object Name
The “exposed to BACnet” name for this history. By default, the entire component path under the station’s History is included, using period (“/”) delimiters between
parent.childlevels. This enforces (externally) the BACnet requirement for unique names for all objects in a device.
You can shorten or edit object name, either now or later. However, please note that each Object Name should be unique among
all server descriptors under the Export Table.
-
Type
Type of descriptor, in the Add dialog it is:
Bacnet Niagara History Descriptor.In any subsequent Edit dialog, this cannot be changed.
-
Object Type
Read-only reflection of the “BACnet Object type” exposed, in this case always:
Trend Log. -
Inst Num
The instance number portion of this object’s “Object ID,” which must be unique within the station for this (exported) BACnet Trend Log object type. By default, the export manager enforces this.
-
Export Ord
Station’s Ord location of the source history, using standard history Ord notation.
-
Description
Optional text string; this appears as the Description property value in the exposed BACnet object.
After creation (adding) Bacnet log descriptors, note that each descriptor also has additional properties accessible in its property sheet, along with those seen in the Add and Edit dialog. See the next section, Properties of Bacnet file descriptors for more details.